Osteo-cementum Producing Odontogenic Myxomas. A Literature Review of a Distinctive Variant

Odontogenic myxoma (OM) is a benign neoplasm of mesenchymal origin with growth characteristics, clinical behaviour and radiographic presentation similar to those of ameloblastoma. It is an intraosseous neoplasm characterized by stellate and spindleshaped cells embedded in loose myxoid or mucoid extracellular matrix. Although sometimes bony islands that represent residual trabeculae are found throughout the lesion, the formation of osteocement-like calcified spherules within the tumour is an extremely rare phenomenon.

We report a very rare case of an OM of the left maxilla exhibiting osteo-cementous metaplasia within the substance of the tumour and beyond the facial skeleton, in the nasopharynx. A review of all four similar cases previously reported in the literature is also presented.

Whether or not this property to produce significant amounts of bone can be associated with a different biological behavior for this specific variant of OM remains to be proved with the study of more similar cases.